1. Field of the Invention
The present invention is related to a weather strip which is mounted on a door opening circumferential portion of a vehicle.
2. Description of the Related Art
Generally speaking, weather strips are provided on door opening circumferential portions of vehicles such as automobiles. As indicated in FIG. 4, a weather strip 70 has been equipped with a trim portion 72 having a substantially U-shaped form of a sectional plane thereof, and a seal portion 73 having a hollow portion 74. The trim portion 72 is mounted on a flange portion 71 provided along a door opening circumferential portion of a vehicle. The seal portion 73 is provided in such a manner that the seal portion 73 is projected from the trim portion 72 to an outer side of the vehicle. Then, when a door 75 of the vehicle is closed, the seal portion 73 is contacted to a circumferential portion of the door 75 under pressure, so that the door 75 is sealed with respect to a vehicle body (refer to, for instant, patent publication 1). It should be understood that as materials for constructing weather strips, the below-mentioned materials are known: ethylene-α-olefin non-cojugated diene copolymer (EPDM), olefin-series thermoplastic elastomer (TPO), and the like are known.    Patent Publication 1: JP-A-2004-237900
As previously described, the seal portion 73 of the weather strip 70 is deformed in such a manner that since the seal portion 73 is contacted to the circumferential portion of the door 5 under pressure, this seal portion 73 is crushed. However, as indicated by a two-dot and dash line of FIG. 4, due to such a cause as right-fitting fluctuations of the door 75, there are some possibilities that under closed condition of the door 5, a portion of the seal portion 73 is bent to the inner side of the hollow portion 74 in such a manner that this portion is separated from the circumferential portion of the door 75, and thereafter, this portion is concaved inside the hollow portion 74, while the portion of the seal portion 73 is contacted to the circumferential portion of the door 75 under pressure. In particular, if such a deformed condition of the seal portion 73 is maintained for a long time, then the following possibilities may occur: That is, the deformed shape of the seal portion 73 cannot be returned to the original shape thereof while the above-described concave is formed. Accordingly, there is such a risk that qualities of outer appearances of the weather strip 70 may be deteriorated due to the above-described reason.